Standardizing computed tomographic assessment of the mesopancreas in pancreatic cancer patients

PURPOSE: The mesopancreas (MP), the dorsal area of the pancreas, is infiltrated in the majority of patients with pancreatic ductal adenocarcinoma of the pancreatic head (hPDAC) and is associated with an increased risk of incomplete resection. Current radiographic resectability criteria primarily focus on tumor involvement of major peripancreatic vessels. However, the dorsal resection margin, represented by the mesopancreas, is not explicitly considered in current staging concepts. The aim of this study was therefore to standardize a quantitative radiographic assessment of the mesopancreas and to correlate these findings with histopathology. METHODS: Radiographic parameters of the primary tumor and the mesopancreas were evaluated in 173 patients with hPDAC who underwent upfront surgery. Patients were stratified according to NCCN anatomical resectability criteria. Mesopancreatic dimensions (mm) and density (HU) were analyzed on preoperative multidetector computed tomography (MDCT). Nineteen patients served as a reference group. Histopathological evaluation followed the Leeds Pathology Protocol (LEEPP). RESULTS: 124 patients (71.7%) were classified as primary resectable and 49 (28.3%) as borderline resectable. Mesopancreatic infiltration was present in 125 patients (72.3%). Resectability classification was not associated with mesopancreatic infiltration (p = 0.344; OR 1.5). The median density of the mesopancreas in hPDAC patients was 3 HU. Increased mesopancreatic density correlated with histopathologically confirmed mesopancreatic infiltration (p = 0.005), with an optimal threshold of -9 HU. In subgroup analysis, this association remained significant in primary resectable patients (p = 0.021) but not in borderline resectable tumors (p = 0.780). Additionally, higher mesopancreatic density was associated with poorer disease-free survival in primary resectable patients (p = 0.040). CONCLUSION: Increased mesopancreatic density on preoperative MDCT correlated with histopathologically confirmed mesopancreatic tumor infiltration. Radiographic assessment of mesopancreatic density may therefore provide additional information for preoperative risk stratification.